Which value is NOT listed among the four primary ABG tests in the material?

• A. BPH
• B. CO2
• C. pH
• D. Bicarb

Answer: (C)

Arterial blood gas interpretation centers on four core measurements that describe acid-base status and oxygenation. In most teaching, these include the blood’s acidity/alkalinity (pH), the respiratory driver (PaCO2), the metabolic buffer (HCO3−), and the oxygen level (PaO2). In the material you’re using, the four primary values listed do not include one of these four, so that particular value is identified as not listed. It’s helpful to remember how these pieces relate: pH shows the overall acidity, while PaCO2 reflects respiratory influence and HCO3− reflects metabolic buffering; together with PaO2 they give a complete picture of gas exchange and acid-base balance. If your study guide groups the values differently or treats pH as a derived outcome rather than a primary listed value, that would explain why it’s the one not included in that specific set.